使用 rvest 或 xml 解析指向下一页的链接？

Question

致力于学习从网站上抓取数据。我一直在玩 rvest 包，并掌握了如何使用选择器小工具等提取节点。对于一个快速项目，我希望从飞行网站中提取数据，将其转换为我的数据框以后可以子集并通过电子邮件发送给我有用的航班。我正在使用的代码都在下面。

library(rvest)
reg = paste("http://www.secretflying.com/usa-deals/") 

#read the text from the flight deal-----------
fly_deals = read_html(reg)
fly_deals = html_nodes(fly_deals, ".entry-title a")
fly_deals = html_text(fly_deals)
fly_deals = as.data.frame(fly_deals)

#add link (not sure how to access the link)
fly_deals$correpsonding_link = 'corresponding_link'

#last step would filter out for NYC
fly_deals = fly_deals[grepl("NEW YORK", fly_deals$fly_deals),]

我现在想做的是访问与每一行（也就是每个节点）关联的页面，这样我就可以使用相应的链接构建另一列，该链接可以直接从我的电子邮件中访问。因此最终产品看起来像这样：

感谢任何帮助！

Answer 1

试试：

library(rvest)

deals_link <- "http://www.secretflying.com/usa-deals/"
deals_info <- deals_link %>% read_html() %>%
  html_nodes(".entry-title a")

fly_deals <- data.frame(deals = html_text(deals_info), correpsonding_link = html_attr(deals_info,"href"))

fly_deals[grepl("NEW YORK", fly_deals$deals),]

输出：

 deals                                                                  
 NON-STOP FROM NEW YORK TO CARTAGENA, COLOMBIA FOR ONLY $328 ROUNDTRIP  
 XMAS & NEW YEAR: NEW YORK TO THE TURKS & CAICOS FOR ONLY $231 ROUNDTRIP
 NEW YORK TO BOSTON (& VICE VERSA) FOR ONLY $66 ROUNDTRIP               
 correpsonding_link                                                         
 http://www.secretflying.com/2016/new-york-cartagena-colombia-296-roundtrip/
 http://www.secretflying.com/2016/hot-new-york-turks-caicos-58-one-way/     
 http://www.secretflying.com/2016/new-york-boston-vice-versa-66-roundtrip/ 

我希望这会有所帮助。